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Apache Lucene (module: facet)
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* Taxonomy of Categories.
*
* Facets are defined using a hierarchy of categories, known as a Taxonomy. For example,
* the taxonomy of a book store application might have the following structure:
*
*
* - Author
*
* - Mark Twain
*
- J. K. Rowling
*
*
*
*
* - Date
*
* - 2010
*
*
* - March
*
- April
*
* - 2009
*
*
* The Taxonomy translates category-paths into integer identifiers (often termed
* ordinals) and vice versa. The category Author/Mark Twain
adds two nodes to
* the taxonomy: Author
and Author/Mark Twain
, each is assigned a
* different ordinal. The taxonomy maintains the invariant that a node always has an ordinal that is
* < all its children.
*/
package org.apache.lucene.facet.taxonomy;